128a_su09_hw6_sol

# 128a_su09_hw6_sol - MATH 128A, SUMMER 2009: HOMEWORK 6...

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Example code to solve the numerical problems: % Create the table of solutions (by 8 methods) to the IVP from HW6. % t(i+1): Value of t_i % w(i+1,j): Value of w at t_i using method #j % names{j}: Name 7-letter-long name for method #j % Set up the IVP: f = @(t,y) 1+y./t; h = 0.25; t = 1:h:2; n = length(t)-1; w(1,1:8) = 2; for i = 1:n names{1} = ’ Exact ’; w(i+1,1) = t(i+1).*(log(t(i+1))+2); names{2} = ’Taylor2’; df = @(t,y) 1./t; % Total derivative of f(t,y(t)) w(i+1,2) = w(i,2) + h*f(t(i),w(i,2)) + h^2/2*df(t(i),w(i,2)); names{3} = ’M.Euler’; k1 = h*f(t(i) ,w(i,3) ); k2 = h*f(t(i)+h,w(i,3)+k1); w(i+1,3) = w(i,3) + 1/2*k1 + 1/2*k2; names{4} = ’A-B (2)’; if i == 1 w(i+1,4) = w(i+1,1); % Use exact value for w_1. else w(i+1,4) = w(i,4) + h/2*(3*f(t(i),w(i,4)) - f(t(i-1),w(i-1,4))); end names{5} = ’A-M (1)’; % Algebraic solution to w = a + b*f(t,w): % w = a + b + (b/t)w ==> (1-b/t)*w = a+b sol = @(a,b,t) (a+b) ./ (1-b./t); w(i+1,5) = sol(w(i,5) + h/2*f(t(i),w(i,5)), h/2, t(i+1)); names{6} = ’APC 1,1’;

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## This note was uploaded on 04/06/2010 for the course MATH various taught by Professor Tao/analysis during the Spring '10 term at UCLA.

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128a_su09_hw6_sol - MATH 128A, SUMMER 2009: HOMEWORK 6...

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